Abnormal pregnancies associated with deviation in progestin and estrogen profiles in late pregnant mares: A diagnostic aid.

The research article investigates how differences in progestin and estrogen levels during late pregnancy in horses could be used as diagnostic indicators for detecting abnormal pregnancies. The study also examines the relationship between hormonal changes following treatments and the survival chances of foals.

Study Objectives and Methods

• The core objectives of this study were to compare progestin and estrogen concentrations in mares with both normal and abnormal pregnancies during late gestation, evaluate the diagnostic value of these hormone levels, and investigate how these hormone levels vary after treatment and how this impacts foal survival.
• Blood samples were collected from 459 pregnant mares at regular intervals between the 201st day of gestation and foaling. The blood samples were analysed for their progestin and estrogen levels using a time-resolved fluoroimmunoassay with anti-progesterone and anti-17β-estradiol antibodies.
• Cutoff values that would serve as indicators differentiating between the healthy and at-risk groups were established using receiver-operating characteristic (ROC) curve analysis.

Findings

• The study found noteworthy differences in progestin and estrogen concentrations between healthy foals and lost foals during the 241st to 320th days of gestation. These findings suggest the potential of hormone concentrations as markers for pregnancy outcomes.
• Pregnancies were predicted based on the established cutoff values of serum progestin and estrogen concentrations for each 20-day interval during gestation, further solidifying the diagnostic utility of these hormonal levels.
• All mares that showed improved progestin or estrogen levels after treatment gave birth to healthy foals. Conversely, worsening hormone levels after treatment corresponded with higher rates of foal loss, particularly when treatment was administered between the 201st and 290th days of gestation.
• Mares with high progestin and low estrogen levels had a higher likelihood of aborting or delivering dead foals during mid-to-late gestation, indicating the significance of hormonal balance in successful horse pregnancies.

Implications and Conclusion

• The findings support the notion that monitoring progestin and estrogen concentrations could be a beneficial diagnostic tool for detecting abnormalities in late pregnancy in mares, enabling early intervention strategies.